The Cytochemistry and Morphology Core facilIty comprises three units: a Light Microscopy Unit, an Electron Microscopy Unit, and an image Analysis Unit. This Core Facility is designed to provide accessible, state-of-the art microscopy for funded investigators. A range of services and techniques are provided including routine light photomicroscopy utilizing inverted microscopes or a Zeiss Photoscope III with phase contrast, differential interference contrast, epifluorescence, or interference reflection optics, high resolution immunocytochemistry of 5, 0.5, and 0.1 micromoles frozen sections, either double or single labeled, conventional electron microscopy of plastic sections, In situ hybridization, including labeling of sections with antibodies against protein moieties, scanning confocal microscopy, and image analysis of cells, tissue sections, or photographic negatives using a Zeiss IBAS image analyzer. Drs. Susette Mueller and Wen-Tien Chen are co-directors, and together with the microscopist, Dr. Maozheng Dai, have provided state-of-the-art microscopy instrumentation and expert assistance for studies in tumor cell biology. The instrumentation and personnel have been centralized over the last two years in the Preclinical Science Building. The use of the Core facility has expanded, with the light and image analysis units becoming more heavily utilized. An additional 25% time/effort of the image analysis technician is requested to support an increasingly sophisticated utilization of the Image Analysis Unit. The proposed support for the Image Analysis Technician, Mr. Zitzmann, will allow an increase in powerful image analysis applications tailored for specific research needs. Members from seven programs of the CCSG application, and from nine departments have utilized the Cytochemistry and Morphology Core in the last two years, including work from 23 peer-reviewed funded projects.